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update:

I did a real app benchmark of this patch by running one of
the unit tests from 
PyXML-0.6.6.  (Which one?  The one that I guessed would
favor my optimization 
the most.  Unfortunately I've lost my notes and I don't
remember which one.)

I also separated out the "unroll strcmp" optimization from
the "use macros" 
optimization on request.

I have lost my notes, but I recall that my results showed
what I expected: 
between 0.5 and 3 percent app-level speed-up for the unroll
strcmp optimization.

Interesting detail: a quirk in GCC 3 makes the unroll strcmp
version is slightly 
faster than the current strcmp version *even* in the
(common) case that the 
first two characters of the attribute name are *not* '__'.

What should happen next:

1.  Someone who has the authority to approve or reject this
patch should tell me 
what kind of benchmark would be persuasive to you.  I mean:
what specific 
program I can run with and without my patch for a useful
comparison.  (If you 
require more than a 5% app-level speed-up, then let's give
up on this patch now!)

2.  Someone volunteer to test this patch with MSFT compiler,
as I don't have one 
right now.  Some people are still using the Windows
platform, I've noticed [1], 
so it is worth benchmarking.  Actually, someone should
volunteer to benchmark 
GCC+Linux-or-MacOSX, too, as my computer is a laptop with
variable-speed CPU and 
is really crummy for benchmarking.

By the way, PEP 266 is a better solution to the problem but
until it's 
implemented, this patch is the better patch.  ;-)

Note: this is one of those patches that looks uglier in
"diff -u" format than in 
actual source code.  Please browse the actual source
side-by-side [2] to see how 
ugly it really is.

Regards

Zooko

[1] http://www.google.com/press/zeitgeist/jan02-pie.gif
[2] search for "class_getattr" in:
    http://zooko.com/classobject.c
    http://zooko.com/classobject-strcmpunroll.c

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Security and Distributed Systems Engineering
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